Review: DJI Zenmuse Xt

Thermal Imaging Hits the Big Time! This article was originally published in The Drone Mag’s April/May 2016 issue. by Patrick “Lucidity” Sherman, Roswell Flight Test Crew

The DJI Zenmuse XT incorporates a FLIR thermal imaging camera and three-axis stabilization, and is capable of providing real-time video via Lightbridge and the DJI Go app. It is expected to start shipping in the first quarter of 2016, and will be compatible with the Inspire One and Matrice 100 quadcopters.At the rollout event in San Francisco’s Marina Theater, DJI showed off an alpha version of the DJI GO app integrating thermal imaging from the Zenmuse XT camera gimbal.

“Star Wars: The Force Awakens” wasn’t the only big premier to hit theaters this past December. DJI and FLIR, the world’s leading manufacturer of thermal imaging cameras, announced a blockbuster deal to make the technology easier to use and more accessible for drone pilots everywhere. We sent the Roswell Flight Test Crew on location for an exclusive report from the event.

Like peanut bu er and chocolate or R2-D2 and C-3PO, there are some pairings that are just meant to be — and the combination of drones and thermal imaging is definitely one of them. And, you don’t just have to take my word for it. Here is what Jeff Frank, senior vice president for global product strategy at FLIR, told a gathering of technology reporters packed into San Francisco’s Marina Theater.

“We’re sensor manufacturers and at the end of the day, a drone really only has one purpose: to position a sensor in three- dimensional space. By being able to position those sensors in 3D space, it completely changes the value proposition in a very, very positive way — so we view drones as an important extension to the capability of what we do.”

Here at the Roswell Flight Test Crew, we’ve been flying FLIR thermal imaging cameras on drones for more than four years now, patching their ghostly, Bizzaro-world rendering of the environment into our First-Person View (FPV) systems. That allowed us to fly demonstrations for firefighters — peering through smoke and watching heat move through burning buildings — as well as maneuvering in total darkness, relying on the thermal energy radiated and reflected by objects to perceive the world around us. It has been extremely cool, but it required a non- negligible measure of technical skill to make it work. That was the hurdle that DJI set out to overcome by building a relationship with FLIR, according to the company’s director of strategic relationships, Michael Perry.

This airborne thermal image of a search and rescue training exercise shows how human beings stand out a luminous figures against the background in a wilderness setting. Notice that the camera is using a “white-hot” color palette, so that the warmest object in the field of view is displayed as white, the coldest is black, and objects at intermediate temperatures are displayed as shades of gray.

“So far, the only real option people have had is to take small cameras like the FLIR Vue Pro and install it on the bo om of one of our smaller quadcopters and setup a video transmission systems — and that ends up being a bridge too far for a lot of first-time users of aerial equipment,” Perry said.

DJI users have been especially interested in adding thermal imaging capabilities to the Matrice 100 platform, according to Perry, who added, “We’ve been ge ing requests for that on an almost daily basis.”

The answer: the Zenmuse XT, a plug- and-play solution for both the Matrice 100 and the Inspire One that provides three-axis gimbal stabilized thermal imaging and is fully compatible with Lightbridge and the DJI GO app.

Although thermal imaging works equally well day or night, it is occasionally confused with night vision tech- nology — and it can make objects, especially people, easier to identify in low-light environments. The image on the left was captured with a conventional, visible-light camera, approximating the human eye. On the right, the same scene is viewed through a FLIR thermal imaging camera.Thermal imaging has value that goes well beyond low-light environments. In this side-by-side comparison of a firefighting training exercise, the visible-light image on the left is completely obscured by smoke, where as the thermal image on the right provides a clear view of the environment.

THERMAL WHO?

Before you get too excited about having your very own airborne thermal imaging camera, let’s take a moment to understand how this technology works. By way of comparison, consider a conventional, visible light camera — of the sort you no doubt have on your drone, as well as your smart phone, the back bumper of your car, above the screen on your laptop and, I don’t know, maybe your toaster by the time this article is in print.

Regular cameras are ubiquitous in this modern age and we all have an intuitive understanding of how they work, because it’s basically the same way our own eyes work. Photons of light are either Demi ed from some source (the sun, a light bulb) or reflected off of something in the environment (a rock, a tree), then they pass through a lens which focuses the photons onto a light-sensitive receptor. In the case of the human eye, that receptor is our retina. On a camera, it’s a sensor. Either way, the receptor creates an image which reveals to us information about the physical world: the location, shape and color of objects, basically.

A thermal imaging camera works in precisely the same way, except that the photons it uses to create an image are invisible both to our unaided human eyes and regular cameras.

They are thermal photons — heat, basically — and just like visible light photons, they are either Demi ed by environmental sources (a running car engine, a living human body) or reflected off objects, then focused and captured to create a picture of the world. Of course, from the very first moment we opened our eyes, we’ve become accustomed to seeing the world as it appears to us through visible light. Therefore, thermal images can seem a li le strange to us when we first see them.

One example: at 98.6 degrees Fahrenheit, human beings are o en the warmest thing you’ll find in a particular scene. Consequently, they are radiant — like living LEDs — and tend to stand out against the background.

Also, glass is transparent to visible light photons, but it’s opaque to thermal photons — so you can’t see through windows with a thermal imaging camera. However, while smoke obscures visible light, thermal photons pass right through it, which is why FLIR systems are of such enormous value to firefighters.

One more crucial thing to understand: thermal images make visible to us variations in temperature, so there are no natural “colors” associated with them. Consequently, the camera can provide us with myriad different ways to see the world: the hottest thing in the frame can be white, or black, or red, or green — it’s up to you.

When you are using a thermal imaging camera, you can choose from among different color pale es and select whichever one helps you best make sense of what you are seeing.

In keeping with the film premier theme that marked the announcement of the new partnership between FLIR and DJI and their collaboration on the Zenmuse XT camera gimbal, the Marina Theater’s lobby was festooned with movie posters illustrating the potential applications of airborne thermal imaging systems.

EASY AS DJI

Thermal imaging has been in use by the military, first responders, scientists and engineers for decades. These capabilities are not new, but what this new partnership between DJI and FLIR has done is make it accessible to a much larger group of users by making it less expensive and easier to use. We’ll know how much less expensive sometime in the first quarter of 2016 when pricing for the Zenmuse XT is announced, but if the Vue and the Vue Pro — FLIR’s previous entries into the drone market — are any indication, they will cost significantly less than the Tau camera cores that served as the model for them. Like the Tau and the Vue cameras that came before it, the Zenmuse XT will be available at several different resolutions: 640 by 512 pixels and 336 by 256 pixels.

“These are state-of-the-art, high resolution cameras,” Frank explained. “In the infrared industry, 640 by 512 is considered a very high- resolution image.”

Ease of use will be provided through seamless integration into the DJI GO app, using the company’s Lightbridge technology. That’s right: the same Android or iOS app that you use to watch your visible-light video in real time and change your camera se ings will work with the Zenmuse XT.

“You will have a wide variety of options for controlling the camera from a great distance — up to five kilometers,” said Perry. “Not only are you able to see what the camera is seeing, you are able to angle the camera, you are able to spot meter, you’re able to get on-the-spot temperature readings for objects you’re seeing from the sky. This is a really powerful tool that will make it easy for anybody to plug-and-play, get up in the air and get the information that they are looking for.”

Even without training in thermography or utility inspection, an average person could likely identify which of the two transfer coils seen in this image is about to fail, simply from observing the build-up of excess heat.

So, what information are people likely to be looking for, once they have their very own airborne thermal imaging cameras? The tactical applications, like search and rescue or firefighting seem so obvious as to not require additional explanation. If you’d like some, check out our YouTube channel to ride along with us as we test out all of these different scenarios. There are many other, less intuitive, possibilities such as infrastructure inspection. Faults in electrical power systems, from transformers to solar cells, are o en visible first as temperature variations which are invisible to the human eye, but obvious to a thermal imaging camera. Precision agriculture could also benefit from a thermal eye in the sky.

“The important thing is that we’ve already seen a lot of applications of aerial technology just using the visible spectrum across these different fields,” Perry said. “However, we feel like adding the thermal layer is going to open up a new range of applications in each one of these industries and expand the creative and innovative uses of this technology.”